What is Gravity

[imatfaal]

 

OK. I see what you mean. All parts of the object would be undergoing acceleration except that central point. Which, ironically, would be the point of greatest gravitational potential (or, equivalently, space-time curvature).

 

Least gravitational potential - the greatest is zero at infinity. You would have to do work to move it away from that central spot - ie anywhere else has higher potential

[hoola]

yes, the point at center of mass is nothing special, just a place where gravity cancells. This is true if the equivalence principle holds, I would think. The main idea that gravity is "curved space" seems to me to indicate that space's constituent virtual particles have their "appearance/disappearance" orbits disturbed...but why does matter disturb them, if this idea can be continued further?

[Strange]

 

Least gravitational potential - the greatest is zero at infinity. You would have to do work to move it away from that central spot - ie anywhere else has higher potential

 

Doh. Of course.

The main idea that gravity is "curved space" seems to me to indicate that space's constituent virtual particles have their "appearance/disappearance" orbits disturbed...

 

I am not aware of any connection between the geometry of space-time and virtual particles. Do you have anything that explains that?

[hoola]

from the casimir experiments, the overall frequency spectrum of the VPs is restricted within material objects, such as "close gap" of the plates. So the forces of these particles between plate should be less than the forces present in space, and the emptier the space, the higher, to a practical maximum. The earth would be less energetic in this respect, as it tends to be "the plates" excluding particle forces, creating a gradient. The reason an object accelerating in space interacts with a similar premise is a little harder to see...

[Strange]

The Casimir force has nothing to do with gravity and space-time curvature.

[hoola]

probably you are right, however could not these same particles be responsible in the larger sense, for the cosmic expansion? If they are "pushing" down on earth, they are pushing everything, including each other...stretching space out, and filling in gaps where the stretching gets above a certain plank-like distance, from quantum uncertainties of position...and while the correspondence between casimir and gravity/space time may be somewhat remote, it seems that they are interacting in some way...how could two such things go about the universe and ignore each other?

Edited March 1, 2015 by hoola

[Strange]

probably you are right, however could not these same particles be responsible in the larger sense, for the cosmic expansion?

 

Expansion (like gravity) is already explained by GR. If you suggest an alternative cause, then you need to explain why GR is wrong. (When it works so well.)

[hoola]

but what causes lambda? I am not saying GR is wrong, just trying to identify lambda...

and GR (probably) identifies a low hanging fruit of overall gravitational function, but not the underlying mechanism, with this curved space thing...

Edited March 1, 2015 by hoola

[Strange]

but what causes lambda? I am not saying GR is wrong, just trying to identify lambda...

 

Do you mean, what causes the accelerating expansion? No one knows.

 

and GR (probably) identifies a low hanging fruit of overall gravitational function, but not the underlying mechanism, with this curved space thing...

 

Why isn't the curvature of space-time an "underlying mechanism"?

[Mordred]

Actually the curved space aspect is easy to understand once you recognize its a description of energy/mass density relations. Treat it as an ideal gas.

 

http://cosmology101.wikidot.com/universe-geometry

page 2

 

http://cosmology101.wikidot.com/geometry-flrw-metric/

As far as what keeps Lambda constant is the mystery.

[michel123456]

Actually the curved space aspect is easy to understand once you recognize its a description of energy/mass density relations. Treat it as an ideal gas.

 

 

I fail to understand when it happens inside a body, together with chemical electromagnetic forces that keep it together.

[hoola]

"Do you mean, what causes the accelerative expansion, no one knows"......I had long presumed that was due to the effects of the stretching of space occuring at the same rate (lambda), within all points of space....accumulatively over great distances to add up to the exponential expansion...

[Strange]

"Do you mean, what causes the accelerative expansion, no one knows"......I had long presumed that was due to the effects of the stretching of space occuring at the same rate (lambda), within all points of space....accumulatively over great distances to add up to the exponential expansion...

 

There are two things here:

 

The recessional speed of (distant) galaxies is proportional to distance - that is just a geometric effect of uniform expansion that can be demonstrated by some simple drawings on paper.

 

The rate at which the universe is expanding is (appears to be) increasing. The reason for this is not known and is labelled "dark energy" (because it is unknown [dark] but can be modelled as a cosmological constant, lambda, representing the energy of space).

Edited March 2, 2015 by Strange

[hoola]

"why isn't the curvature of space the underlying mechanism?"....well, why would mass curve space at all? What is the underlying steps of the relationship that ends with the curving of space? What way does space even know that it's near an object and respond to it by curving...along that line of reasoning...this is why I like the "distorted orbit" idea of virtual particles as a repesenative model of the curvature. That goes little to explain curvature, but at least seems to allow a physical mechanism to the apparent effect......and perhaps a vehicle for extrapolating further into a proposed mechanism....

but of course the recession velocity of the extremes are accelerating....just what you would expect without thinking lambda or dark energy, if you like, is getting bigger...the longer the perceived distance, the more the little stretches get added

Edited March 2, 2015 by hoola

[Strange]

"why isn't the curvature of space the underlying mechanism?"....well, why would mass curve space at all?

 

Because that is what mass is.

 

"Why would electric charges have charge? What is the underlying steps of the relationship that ends with the electric field?"

 

 

but of course the recession velocity of the extremes are accelerating.

 

They are not accelerating (because in their local frame, they are not moving). Their recessional velocity is increasing (as they must, for purely mechanical reasons if there is uniform expansion) but that is not what is meant by "accelerating expansion".

[hoola]

right, I agree, the regions obey physical laws within them locally and only appear golbally as not....so dark energy to be the same everywhere....

to say "that is what mass is" and leave it there is like saying a car moves, without expanding on why it moves....gotta have an engine in it....fuel for the engine...etc..Same thing for electric charge....I don't think either are fundamentals. I think there is a description that underlies all physical observable phenomena, each with it's unique non-physical algorithmic structure of mathematics..as it interacts with other algorithmic discriptive elements....(alpha prime)

Edited March 2, 2015 by hoola

[Strange]

right, I agree, the regions obey physical laws within them locally and only appear golbally as not....so dark energy to be the same everywhere....

to say "that is what mass is" and leave it there is like saying a car moves, without expanding on why it moves....gotta have an engine in it....fuel for the engine...etc..Same thing for electric charge....I don't think either are fundamentals. I think there is a description that underlies all physical observable phenomena, each with it's unique non-physical algorithmic structure of mathematics..as it interacts with other algorithmic discriptive elements....(alpha prime)

 

So let's say someone comes up with an underlying mechanism for mass or charge. Let's call it "X". Would you be satisfied? Or would you say, "what is the underlying mechanism of X? why X?"

 

I am not saying that one shouldn't ask questions or try to understand things more deeply. Just that it doesn't always make sense to ask what the deeper explanation is (the word "mechanism" is particularly troublesome; as if you expect everything to be mechanical at some level - a steam-punk version of advanced physics).

 

I'm sure there will be a theory that goes beyond GR in future. It may (as several attempts currently appear to indicate) describe things in terms of geometric primitives (e.g. causal dynamical triangulation) with space, time, gravity and quantum theory all being emergent properties. (But it will still have to be equivalent to curved space-time at the appropriate level. In the same way that GR reduces to Newtonian force of gravity in the low energy domain.)

 

And then people will ask "why these geometric primitives? why do they have these properties?" etc.

[Mordred]

Well I know everyone here was involved in the "what is space thread where I explained dove curvature, so I'll just repost the thread link.

http://www.scienceforums.net/topic/87620-what-is-in-space/page-2#entry854913

[jurgiessel]

Hallo Zen.

 

Same here. I have labored over this for some time. Would you be interested in reviewing my work? It is amazingly simple and I can't get over that nobody else has come up with it. Or maybe it is all wrong. It would be nice to have some feedback. If you care to take a look, please go to jurgiessel.com

 

Thanks ahead of time,

 

Jurgen

[imatfaal]

!

Moderator Note

 

 

Hallo Zen.

 

Same here. I have labored over this for some time. Would you be interested in reviewing my work? It is amazingly simple and I can't get over that nobody else has come up with it. Or maybe it is all wrong. It would be nice to have some feedback. If you care to take a look, please go to jurgiessel.com

 

Thanks ahead of time,

 

Jurgen

 

Jurgen

 

Please don't post speculative personal ideas in the main fora. There is a Speculation Forum for that exact purpose. Thanks

 

[jajrussel]

But even in free fall a massive object exerts gravity upon other objects.

You are right. It is a necessary component of attraction.

[jajrussel]

The nature of attraction is to close the gap, with gravity the seemingly ultimate purpose is to occupy the same space. Other forces may postpone, or interfere with this purpose, but they never illuminate this desire to close the gap, and occupy the same space.

 

Electromagnetism, has a simular attribute of attraction, but seemingly not to the same purpose. It is more like to fill a void.

 

I believe that I am correct that in both cases one result is acceleration, with gravity a change of speed and direction, while with Electromagnetism simply a change of direction.

 

With gravity the ultimate purpose of occupying the same space one might be tempted to say that with singularity, goal achieved, but apparently not from the singularitie's point of view.

[Asimov]

Captainzen: Leaving out artificial gravity is irrelevant as it is no different than gravity induced by mass or that by an elevator. It is acceleration pure and simple, hard to visualize. In an elevator accelerating up you feel Earth's gravity plus the gravity of the acceleration by the elevator.

 

Gravity has been described as a geometrical property of space-time. A bending of space time. Like a bowling ball on a waterbed. Never seen that though. It is as if mass is accelerating through time. I visualize it that way. It may not be possible to unify with electromagnetism, weak, and strong forces unless they too are a geometrical property of space time. They have not found gravitons. May not. I wait.

[jajrussel]

If you are in the center of a box that is in free fall, floating so to speak because you are also in free fall with the same acceleration as the box. The force you feel is null. Then another force is applied to the box from any direction. From your perspective the box is moving toward you. The force you feel is still null. Until you contact the box. Then the force you feel is equal to the other force, even though you and the box are still in free fall.

 

Is this correct?

 

As I think about the question I realise the box may no longer be in free fall once the other force is applied to it. Then once you make contact with the box you may no longer be in free fall. None the less you and the box may be perceived as falling.

 

The question still is, is this correct?

 

What I am getting at is that is that if this is correct the force I feel upon contact with the box I may perceive as gravity, and this perception might be more related to acceleration than the boxes mass since the mass of its side is far less than the planet we are both falling toward.

Edited August 3, 2015 by jajrussel

[DARRYELREDMON]

Gravity is ever infinitely small amount of space pulling inward with an infinite amount of force. With in counterbalance with an infinite amount of infinitely small spaces that pull inward with an infinite amount of force. Acting as one single space, our infinite universe. A single gravity differential system, our universe. When in a different balance other than 0g. Repetitive patterns of exchange of the balance of gravity that have mass, such as atoms and other patterns exist as our universe today.

Edited September 17, 2015 by DARRYELREDMON